It is known to provide modular arrangements for use in industrial power distribution which include molded case circuit breakers of standard dimensions that are adapted to be plugged onto busbars to establish their electrical connection, e.g., British Patent Nos. 1,161,030 and 1,181,893. An example of a fuse switch unit utilizing a similar modular arrangement is disclosed in U.S. Pat. No. 4,496,916. The entire teachings and disclosures of these patents are incorporated by reference herein.
Due to the physical constraints of many installations, it is desirable to minimize the width of the distribution board utilizing such a modular arrangement. To overcome this problem, the electrical connections to the modular circuit breaker must be accessed other than from the sides of the module. For safety, the incoming line and bus still must be protected against incidental contact with an operator or with outgoing branch lines.
Another problem encountered by distribution boards using the modular arrangement and handling larger currents is making the electrical connection between the modular switch and the bus. When resilient contact jaws are used by the switch module, the force required to make the electrical connection is large. Installation becomes more difficult if the appropriate force can not be applied in a direct manner.
The art needs a new and improved distribution board which utilizes a framework allowing electrical connections to be made through the rear portions of these modular arrangements wherein set-up, expansion, and replacement of switch modules within a support framework is safe, inexpensive and quick. The present invention provides such an improved distribution board.